KR102458318B1 - Polymer Binder Abrasive Articles and Methods of Making Same - Google Patents

Abstract

Methods of making polymeric binder abrasive articles and precursors thereof using powder layer spraying are disclosed. Polymeric bonded abrasive articles made by the present methods include abrasive articles having arcuate or tortuous cooling channels, single structured abrasive discs, abrasive segments, shaped abrasive particles, and abrasive wheels.

Description

Polymer Binder Abrasive Articles and Methods of Making Same

The present invention relates to polymer bonded abrasive articles and methods of making the same.

Abrasive articles (eg, abrasive wheels, abrasive segments and whetstones) are prepared with abrasive particles (eg, diamond, cubic boron nitride, alumina) in a liquid vehicle (eg, an aqueous solution of phenolic resin, polyvinyl alcohol, urea-formaldehyde resin, or dextrin). or SiC), a glassy binder precursor (e.g., glass frit, ceramic precursor), an optional pore-inducing agent (e.g., glass bubbles, naphthalene, ground coconut or walnut shells or acrylic glass or PMMA) and a temporary organic binder. It can be manufactured by The blended mixture is then placed in a hardened steel mold, which is then heated until the vitreous binder precursor is converted to a vitreous binder matrix.

There are many drawbacks to this manufacturing approach: a special mold is required for each abrasive article shape; Molds are typically expensive and have long lead times to manufacture; Any design change requires the manufacture of a new mold; There are limitations to the shapes that can be formed, and complex shapes with internal structures such as undercuts or cooling channels are generally not possible; Molds wear out and have a limited number of units that can be manufactured per mold; While the mold is being filled with the abrasive mixture, heterogeneous abrasive components and segregation of components that cause density changes can occur, which is readily visible. Moreover, the process is manual and labor intensive.

In one aspect, the present invention relates to polymer bonded abrasive articles, such as rotary polishing tools, finishing wheels and components, abrasive segments, whetstones, and the like, as well as methods of making them. Polymer bonded abrasive articles include features such as, for example, internal flow channels, or complex removal channels on the surface.

Polymer bonded abrasive articles can be manufactured directly by binder jetting three-dimensional (3D) printers, avoiding the need to create molds. In this method, a thin layer of powdered particles, including polymer precursor particles and abrasive particles, is temporarily bonded at a desired location by a jetted binder dispensed by an inkjet print head. The printed powder layer may then be at least partially dried and lowered to spread the next powder layer. The powder spreading, temporary bonding, and drying processes can be repeated to produce a green abrasive article preform, which is then removed from the printer and drawn from the surrounding powder remaining unbonded. The abrasive article preform is then further processed to convert the polymer precursor particles into a polymer matrix containing the abrasive particles and form a polymer bonded abrasive article.

In one embodiment, the present invention is directed to a polymeric binder abrasive article comprising a polymeric binder material having abrasive particles retained therein in a polymeric matrix, the polymeric binder abrasive article extending at least partially through the abrasive article. and at least one of a tortuous cooling channel and an arcuate cooling channel.

In another embodiment, the present invention is directed to a polymer binder abrasive article precursor comprising abrasive particles bonded within a polymer matrix, the polymer binder abrasive article precursor at least one extending at least partially through the polymer binder abrasive article precursor. of meander cooling channels; or at least one arcuate cooling channel extending at least partially through the polymer binder abrasive article precursor.

In another embodiment, the present invention relates to a method of making an abrasive article, the method comprising:

a)

i) depositing a layer of loose powder particles in a defined area, said loose powder particles comprising polymeric binder precursor particles and abrasive particles, said layer of loose powder particles having a substantially uniform thickness , step;

ii) applying a liquid binder precursor material to a predetermined area of the layer of sparse powder particles; and

iii) converting the liquid binder precursor material to a temporary binder material, wherein the temporary binder material is bonded to at least a portion of the abrasive particles and the polymeric binder precursor particles in the predetermined region to form a layer of bonded powder particles. forming steps

A subprocess comprising;

b) independently, performing step a) multiple times to produce an abrasive article preform comprising said bonded powder particles and remaining coarse powder particles, wherein in each step a) said coarse powder particles are independently selected and the liquid binder precursor material is independently selected; and

c) converting the polymeric binder precursor particles in the abrasive article preform to polymeric binder particles, the polymeric binder particles retaining the abrasive particles to form a polymeric binder abrasive article;

includes

The features and advantages of the present invention will be further understood upon consideration of the detailed description as well as the appended claims.

1A-1D show schematic process flow diagrams of one embodiment of a method of making a polymer binder abrasive article.
2 is a schematic cross-sectional view of an exemplary polymer binder abrasive wheel that may be made by the method of the present invention.
3 is a schematic cross-sectional view of an exemplary polymer binder abrasive wheel that may be made by the method of the present invention.
4 is a schematic perspective view of an exemplary polymer binder abrasive segment that may be produced by the method of the present invention.
5 is a schematic perspective view of a polymer binder abrasive wheel that may be produced by the method of the present invention.
6A is a schematic perspective view of a single structured abrasive disk that may be produced by the method of the present invention.
6B is a schematic plan view of the single structured abrasive disk of FIG. 6A ;
7A is a schematic perspective view of a single structured abrasive disk 700 that may be manufactured by the method of the present invention.
7B is a schematic plan view of the single structured abrasive disk of FIG. 7A ;
8 is a schematic perspective view of a rotary abrasive tool 800 that may be manufactured by the method of the present invention.
9 is a photograph of a 3D printed part after depowdering for Examples 1 and 2. FIG.
10 is a photograph of a 3D printed part placed on a steel mandrel for Example 1, before curing in an oven.
11 is a photograph of the 3D printed parts of Examples 1 and 2 after curing in an oven.
12 is a photograph of the 3D printed part of Example 3 after powder removal.
13 is a photograph of the 3D printed part of Example 4 after powder removal.
14 is a photograph of the 3D printed part of Example 4 after curing (hardening).
15 is a plot summarizing gloss measurements of surfaces polished with the 3D printed part of Example 1 on a steel mandrel.
Repeated use of reference numerals in this specification and drawings is intended to represent the same or similar features or elements of the invention. Numerous other modifications and embodiments can be devised by those skilled in the art, and fall within the scope and spirit of the principles of the present invention. The drawings may not be drawn to scale.

1A-1D schematically depict an exemplary powder layer spraying process 100 that may be used to make a polymeric binder abrasive article. 1A is a schematic diagram of a 3D printing apparatus 102 that may be used to build up a three-dimensional (3D) model of a shaped abrasive article preform, one layer at a time, layer by layer by repeatedly depositing particulate material over the same area. A non-limiting example is shown. The 3D printer 102 creates an abrasive article preform by converting a 3D computer-aided design (CAD) drawing into a plurality of two-dimensional cross-sectional layers. The 3D printer 102 can deposit successive layers of a mixture of particulates comprising abrasive particles and polymer precursor particles, which are then bonded together in a subsequent step to form a green article, referred to herein as an abrasive article preform. have.

Referring to FIG. 1A , a 3D printing apparatus 102 includes a first chamber 120a having a piston-driven feed platform ram 122a that can be moved in direction A. Ram 122a supports a mixture of particulates 110 , which in some embodiments includes abrasive particles. The powder spreading roller 130 moves in the direction B over the surface 131 of the particulate mixture 110 , and moves the particles in the particulate mixture 110 from the powder material supply platform ram 122a and the chamber 120a to the second chamber. (120b) is displaced substantially uniformly.

The 3D printing apparatus 102 further includes a second chamber 120b having a piston-driven building platform ram 122b moving along direction A. 1B, a defined particle mixture deposition region 140 above the ram 122b contains a deposited layer 138 of a mixture of coarse powder particles comprising abrasive particles and polymer precursor particles, which 110) may be the same as or different from the particles in In some embodiments, the coarse powder layer 138 has a substantially uniform thickness. In some embodiments provided by way of example and not limitation, the thickness of the layer may vary by less than about 100 micrometers, or less than about 50 micrometers, or less than about 30 micrometers, or less than 10 micrometers.

The ram 122b may be adjusted such that the particle mixture deposition region 140 has any desired thickness. In various embodiments, the coarse powder layer 138 is a sprayed liquid binder precursor material (shown in FIG. 1C and discussed below) that is subsequently applied to the layer 138 is a selected region to which the liquid binder precursor material is applied. It can have any thickness, up to about 1 millimeter, as long as it can contact all the particles in it. In some embodiments, the thickness of the coarse powder layer 138 is from about 10 micrometers to about 500 micrometers, or from about 10 micrometers to about 250 micrometers, or from about 50 micrometers to about 250 micrometers, or about 100 micrometers. meters to about 200 micrometers.

The abrasive particles in the coarse powder layer 138 may include any abrasive particles used in the abrasive industry. In various embodiments, the abrasive particles have a Mohs hardness of at least 4, or at least 5, or at least 6, or at least 7, or at least 8, or at least 8.5, or at least 9. In certain embodiments, the abrasive particles include superabrasive particles, which, as used herein, include any abrasive particles having a hardness greater than or equal to that of silicon carbide (e.g., silicon carbide, boron carbide, cubic boron nitride and diamond).

Specific examples of suitable abrasive materials include aluminum oxide (eg, alpha alumina) materials (eg, fused heat treated ceramic and/or sintered aluminum oxide materials), silicon carbide, titanium diboride, titanium nitride, boron carbide, tungsten carbide, titanium carbide, aluminum nitride, diamond, cubic boron nitride (cBN), garnet, fused alumina-zirconia, sol-gel derived abrasive particles, cerium oxide, zirconium oxide, titanium oxide, and combinations thereof do. Examples of sol-gel derived abrasive particles include US Pat. Nos. 4,314,827 (Leitheiser et al.), US Pat. Nos. 4,623,364 (Cottringer et al.); US Pat. No. 4,744,802 (Schwabel); US Pat. No. 4,770,671 (Monroe et al.); and US Pat. No. 4,881,951 (Monroe et al.). Agglomerated abrasive particles comprising finer abrasive particles in a polymeric binder matrix (eg, as described in US Pat. No. 6,551,366 (D'Souza et al.)) may also be used.

To achieve high resolution, in some embodiments the particles in the coarse powder layer 138 are 400 micrometers or less, or 250 micrometers or less, or 200 micrometers or less, or 150 micrometers or less, or 100 micrometers or less. Although they can be sized (eg, by screening) to have a maximum size of less than or equal to 80 microns, or even less than or equal to 10 microns, larger sizes may also be used. The particles in the coarse powder layer 138, including polymeric binder precursor particles, abrasive particles, and optional additional particulate components, have the same or different maximum particle sizes, D ₉₀ , D ₅₀ and/or D ₁₀ particle size distributions. It can have parameters.

In some non-limiting embodiments, the abrasive particles in the coarse powder layer 138 may be at least one of diamond particles, cubic boron nitride particles, or metal oxide particles, and have a density from about 3.5 g/cc to about 3.9 g. It can be /cc. In other embodiments, the abrasive particles in the coarse powder layer 138 may be diamond agglomerates having a density of from about 2.0 g/cc to about 2.2 g/cc.

The particles in the sparse powder layer 138 further include polymer precursor particles. In some embodiments, the polymer precursor particles at least partially include a thermoplastic polymer resin that can be softened to flow around the abrasive particles. The thermoplastic, when at least partially hardened, strengthens and adhesively retains the abrasive particles, allowing polymer bonded abrasive articles to be manufactured having the desired shape for a particular application. Non-limiting examples of suitable thermoplastic resins include polyethylene, polypropylene, polystyrene, acrylics, cyanoacrylates, epoxies, and combinations thereof. The thermoplastic material may be softened by any suitable technique including the application of thermal radiation or actinic radiation, such as UV radiation.

In other embodiments, the polymer precursor particles in the coarse powder layer 138 are, for example, phenolic resins (eg, novolac and/or resol phenolic resins), acrylic monomers (eg, poly(meth)acrylates). , (meth)acrylic acid, (meth)acrylamide, etc., where (meth) represents acrylic or methacryl), epoxy resins, cyanate resins, isocyanate resins (including polyurea and polyurethane resins), alkyd resins , organic thermosetting compounds such as urea-formaldehyde resins, aminoplast resins, silicones, and combinations thereof. These thermosetting compounds, when at least partially hardened or cured, form a covalently cross-linked binder network, which reinforces and adhesively retains the abrasive particles to form a polymer bonded abrasive having the desired shape for a particular application. Let the article be manufactured. The thermoset material may be softened by any suitable technique including the application of thermal radiation or actinic radiation, such as UV radiation.

In various embodiments, the mixture of particulates in the coarse powder layer 138 is from about 1% to about 99% by weight, or from about 5% to about 95% by weight, or from about 7% to about 93% by weight, or about from 10% to about 90% by weight, or from about 20% to about 80% by weight of the polymer precursor particles. In various embodiments, the coarse powder layer 138 comprises from about 1 wt% to about 99 wt%, or from about 5 wt% to about 95 wt%, or from about 15 wt% to about 85 wt%, or from about 20 wt% to about 20 wt% from about 80% by weight, or from about 30% to about 70% by weight, or from about 40% to about 60% by weight of abrasive particles.

More specific examples of suitable powder layers are from about 7 weight percent abrasive particles to about 93 weight percent polymer precursor particles, or from about 93 weight percent abrasive particles to about 7 weight percent polymer precursor particles, or from about 76 weight percent abrasive particles. particles to about 24 weight percent of the polymer precursor particles.

In some embodiments, the coarse powder layer 138 may further include binder precursor particles. The binder precursor particles, when exposed to or reacting with a liquid binder activating liquid in the predetermined area(s) of the powder layer 138, form a binder in the predetermined area(s) of the abrasive particles as described in more detail below. and temporarily combining the polymer precursor particles and the abrasive particles in the coarse powder layer 138 to form an abrasive article preform. In some embodiments, some or all of the sparse powder particles 138 may be coated with a binder precursor material, which activates on the coated particles when exposed to an activating liquid.

In some embodiments, the particles in the coarse powder layer 138 may optionally include other ingredients such as, for example, pore-inducing agents, lubricants, filler particles, processing aids, and mixtures and combinations thereof. Non-limiting examples of pore directing agents include glass bubbles and organic particles. Suitable lubricants include, but are not limited to, graphite, sulfur, polytetrafluoroethylene (PTFE), molybdenum disulfide, and mixtures and combinations thereof. Suitable processing aids include, but are not limited to, flow agents such as fumed silica, nanosilica, stearate, starch, and mixtures and combinations thereof. The additives have little or no adverse effect on the abrasive particles used in the polymer binder abrasive articles.

The particles in the coarse powder layer 138 may be optionally modified to improve their flowability and uniformity of layer spreading. Methods for improving the powder include agglomeration, spray drying, gas or water spraying, flame forming, granulation, milling and sieving.

In some embodiments, the abrasive particles in the coarse powder layer 138 may optionally include one or more coating layers to promote adhesion to the polymer precursor particles, control the total amount of resin in the polymer binder abrasive article, and the like. In one non-limiting example, the abrasive particles may comprise a coating of a phenolic resin prepolymer, such as a resol resin, and may also be coated with a novolac phenolic resin material prior to spreading.

In some embodiments, the particles in the coarse powder layer 138 are formed by a ceramic precursor (eg, alumina), such as bauxite, boehmite, calcined alumina, or calcined zirconia, that when fired converts to a corresponding ceramic form. or a precursor of zirconia).

Referring to FIG. 1C , liquid binder precursor material 170 is sprayed onto predetermined area(s) 180 of loose powder layer 138 by print head 150 of 3D printing apparatus 102 . Accordingly, the liquid binder precursor material is converted into a binder that coats the sparse powder particles in the region 180 and subsequently bonds the sparse powder particles in the predetermined region 180 to each other at least temporarily. Liquid binder precursor material 170 can be any composition that can be converted to a binder material (eg, by evaporation, or by thermal, chemical, and/or radiation curing (eg, using UV or visible light)). This binder material bonds the loose powder particles together according to the ejected pattern (and ultimate 3D shape upon multiple iterations) obtained by programmed movement of the print head 150 .

In some embodiments, the liquid binder precursor material 170 includes a liquid carrier and a polymer. The liquid carrier may comprise at least one organic solvent and one or more of water. Exemplary organic solvents include, but are not limited to, alcohols (eg, butanol, ethylene glycol monomethyl ether), ketones, and ethers, which in some non-limiting embodiments have a flash point greater than 100°C. The choice of a suitable solvent or solvents will typically depend on the requirements of the particular application, such as, for example, the desired surface tension and viscosity, the particulate solid selected, and the like.

In some embodiments, the one or more organic solvents included in the liquid carrier can control, for example, at least one of the drying rate or surface tension of the liquid binder precursor material 170 , or a component (eg, a surfactant ), or may be used as a minor component of any component; An organic cosolvent may be present, for example, in a surfactant added as an ingredient to the liquid carrier. Exemplary organic solvents for liquid binder precursor material 170 include alcohols such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, t-butyl alcohol, and isobutyl alcohol. ; ketones or ketoalcohols such as acetone, methyl ethyl ketone and diacetone alcohol; esters such as ethyl acetate and ethyl lactate; polyhydric alcohols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butylene glycol, 1,4-butanediol, 1,2,4-butanetriol, 1,5-pentanediol, 1, 2,6-hexanetriol, hexylene glycol, glycerol, glycerol ethoxylate, trimethylolpropane ethoxylate; lower alkyl ethers such as ethylene glycol methyl or ethyl ether, diethylene glycol ethyl ether, triethylene glycol methyl or ethyl ether, ethylene glycol n-butyl ether, diethylene glycol n-butyl ether, diethylene glycol methyl ether, ethylene glycol phenyl ether, propylene glycol methyl ether, dipropylene glycol methyl ether, tripropylene glycol methyl ether, propylene glycol methyl ether acetate, dipropylene glycol methyl ether acetate, propylene glycol n-propyl ether, dipropylene glycol n-propyl ether, tripropylene glycol n-propyl ether, propylene glycol n-butyl ether, dipropylene glycol n-butyl ether, tripropylene glycol n-butyl ether, propylene glycol phenyl ether, and dipropylene glycol dimethyl ether; nitrogen-containing compounds such as 2-pyrrolidinone and N-methyl-2-pyrrolidinone; sulfur-containing compounds such as dimethyl sulfoxide, tetramethylene sulfone, and thioglycol; and combinations of any of the foregoing.

The liquid carrier may be entirely water, or it may contain water in combination with one or more organic solvents suitable for dissolving the polymer in the liquid binder precursor material 170 . Preferably, the aqueous carrier contains, by total weight, at least 20% water, at least 30% water, at least 40% water, at least 50% water, or even at least 75% water.

The amount of organic solvent and/or water in the liquid carrier may depend on several factors, such as particularly desired properties of the liquid binder precursor material 170 , such as viscosity, surface tension, and/or drying rate, which in turn may depend on the liquid binder precursor material 170 . may depend on factors such as the type of inkjet printing technology intended to be used with the piezo-type or thermal print head 150 .

The polymer in the liquid binder precursor material 170 may be soluble or dispersible in the liquid carrier. Examples of suitable polymers for the liquid binder precursor material 170 include polyvinyl pyrrolidone, polyvinyl caprolactam, polyvinyl alcohol, polyacrylamide, poly(2-ethyl-2-oxazoline) (PEOX), polyvinyl butyrate. , copolymers of methyl vinyl ether and maleic anhydride, certain copolymers of acrylic acid and/or hydroxyethyl acrylate, methyl cellulose, natural polymers (eg, dextrin, guar gum, xanthan gum). In some embodiments, polyvinyl pyrrolidone may be used with a liquid carrier comprising or predominantly water. If desired, other organic polymers other than those listed above may be used instead of or in addition to this.

Liquid binder precursor material 170 may include one or more free-radically polymerizable or otherwise radiation-curable materials; for example, acrylic monomers and/or oligomers and/or epoxy resins. An effective amount of a photoinitiator and/or a photocatalyst for curing the free-radically polymerizable or otherwise radiation-curable material may also be included. Examples of suitable (meth)acrylate monomers and oligomers and otherwise radiation-curable materials (eg, epoxy resins) can be found, for example, in US Pat. No. 5,766,277 (DeVoe et al.).

In some preferred embodiments, the liquid binder precursor material 170 is essentially free of metal nanoparticles and/or metal oxide nanoparticles (eg, containing less than 1%, less than 0.1%, less than 0.01% nanoparticles, or , even without). As used herein, the term “nanoparticle” refers to particles having an average particle diameter of 1 micrometer or less, or 500 nanometers (nm) or less, or even 150 nm or less.

Alternatively or additionally, the liquid binder precursor 170 may be an aqueous sol comprising ceramic precursors for alumina and/or zirconia. Examples include aqueous boehmite sols and zirconia sols. In such cases, after firing to produce a polymeric binder abrasive article, the liquid binder precursor 170 may have the same or a different composition as the abrasive particles. Details regarding zirconia sols can be found, for example, in US Pat. No. 6,376,590 (Kolb et al.). For details regarding boehmite sols, see, for example, US Pat. Nos. 4,314,827 (Laitacer et al.), US Pat. Ringer et al.), 4,744,802 (Schwabell), 4,770,671 (Monroe et al.), 4,881,951 (Wood et al.), 4,960,441 (Pellow et al.), 5,011,508 (Wald et al.) ), etc.), 5,090,968 (Fellow), 5,139,978 (Wood), 5,201,916 (Berg et al.), 5,227,104 (Bauer), 5,366,523 (Rowenhorst et al.), 5,429,647 (Larmie), 5,547,479 (Conwell et al.), 5,498,269 (Lamier), 5,551,963 (Lamier), 5,725,162 (Garg et al.) and 5,776,214 (Wood) can be found.

In some embodiments, the sprayed liquid binder precursor 170 may be an activating liquid, which reacts or contacts the solid binder precursor particles in the predetermined region(s) of the sparse powder layer 138 , wherein the binder precursor particles react with the binder to temporarily bond the abrasive particles and the polymer precursor particles together in a predetermined region of the binder. In some embodiments, the sprayed activating liquid 170 reacts or contacts a layer of a binder precursor on selected particles within the sparse powder layer 138, which in turn causes the layer of the binder precursor to form a binder in the predetermined area with the abrasive particles and The polymer precursor particles are bonded together.

Referring now to FIG. 1D , the sprayed liquid binder precursor material 170 at least temporarily bonds the sparse powder particles together in a predetermined region 180 of the sparse powder particles 138 to form a layer of bonded powder particles. is converted to a binder material (step 190). The liquid binder precursor material may be converted into a liquid binder in a wide variety of ways, such as, for example, by evaporation of the liquid carrier within the liquid binder precursor material 170 or by melting or softening the liquid binder precursor material. Cooling may be accomplished by any means known in the art (eg, air cooling to room temperature or low temperature quenching).

The above steps are then repeated (step 185 of FIG. 1D ) while changing the area 180 where spraying is performed in selected areas of the coarse powder layer 138 according to a predetermined programmed design, through repetition of FIG. 1D . In step 195 of the three-dimensional (3D) raw abrasive article preform 196 is created layer by layer. At each iteration, the coarse powder particles and the liquid binder precursor material can be independently selected; That is, either or both of the sparse powder particles and the liquid binder precursor material may be the same or different from those of the adjacent deposited layers.

The resulting abrasive article preform 196 is a raw abrasive article comprising powder particles bonded by a binder material as well as any remaining unbonded sparse powder particles. Once sufficient iterations have been performed to form the abrasive article preform 196 , in some embodiments, the abrasive article preform comprises substantially all (eg, at least 85%, 90% of the remaining unbound coarse powder particles). or greater, 95% or greater, or 99% or greater), but this is not a requirement in the process of the present invention.

If desired, multiple particle reservoirs, each containing a different powder, may be used in each step 185 of the process of FIG. 1 . Likewise, a number of different liquid binder precursor materials 170 may be used via a common print head 150 or via separate print heads in some embodiments. Thus, different powders/binders may be distributed in different and discrete regions of the polymeric binder abrasive article. For example, relatively inexpensive but lower performing abrasive particles and/or polymeric binder precursor particles can be introduced into areas of the polymeric binder abrasive article where it is not particularly important to have high performance properties (e.g., away from the abrasive surface). inside) can be relegated.

Powder layer spray 3D printing equipment suitable for making the polymer bonded abrasive articles of the present invention is commercially available, for example, from ExOne, North Huntington, PA. Further details regarding powder bed spraying techniques suitable for practicing the present invention can be found, for example, in US Pat. Nos. 5,340,656 (Sachs et al.) and 6,403,002 B1 (van der Geest). can be found

In step 197 of FIG. 1D , the raw abrasive article preform 196 is further processed to form a polymer binder abrasive article 198 . The additional processing steps 197 can vary widely depending on the intended application, but generally convert the polymer precursor particles in the abrasive particle preform 196 into a polymer matrix that retains or bonds with the abrasive particles in the preform 196 . transform

In some embodiments, the processing step 197 includes heating the abrasive article preform 196 to soften the polymer precursor particles and flow around at least some of the abrasive particles in the abrasive article preform 196 . . The softened polymer precursor particles occupy the interstices between the abrasive particles to form an abrasive article having a matrix. Of course, the temperature to which the abrasive article preform 196 is heated will depend on the polymer precursor and abrasive particles present therein, although in some non-limiting exemplary embodiments the preform 196 may have a temperature between about 150°C and about 350°C; or from about 200°C to about 250°C, or from about 205°C to about 230°C. The preform 196 may be heated by any suitable method including, for example, placing in an oven, using a laser, or applying radiation. In some embodiments, the temperature to which the preform 196 is heated may be sufficient to remove at least some or all of the binder material present in the preform 196 . After the cooling step, the polymer matrix sufficiently retains the abrasive particles so that the resulting polymer binder abrasive article 198 can be used for the selected grinding application.

In another embodiment, the processing step 197 applies actinic radiation, such as, for example, ultraviolet (UV) radiation, to the abrasive article preform 196 to at least partially cure the polymer precursor particles and retain at least a portion of the abrasive particles. forming a polymer matrix and forming a polymer binder abrasive article 198 for

In another embodiment, processing step 197 applies an activating material or a polymerizing material to the abrasive particle preform 196 to at least partially polymerize the polymer precursor particles and form a polymer matrix for retaining at least a portion of the abrasive particles. and forming the polymer binder abrasive article 198 .

It should be noted that the processing step 197 may include one or a combination of heat, actinic radiation or application of a polymerization and activating material, and these processing steps may be performed continuously or in batch form.

In some embodiments, the polymer binder abrasive article 198 may have significant porosity throughout its volume. Thus, in some embodiments, the abrasive article preform 196 may optionally be infused with a solution or dispersion of additional polymeric binder precursor material or grain growth modifier before, during, or after processing step 197 .

The method according to the present invention is suitable for making a variety of polymeric binder abrasive articles 198 that cannot or cannot be readily or easily produced by other methods. For example, interior voids may be included in the polymer binder abrasive article 198 if an outward opening of the abrasive article preform 196 exists for removal of unbound coarse powder. Cooling channels having serpentine and/or arcuate paths that open outward of the polymer binder abrasive article 198 can be readily manufactured using the methods of the present invention. In some embodiments, the polymer binder abrasive articles 198 may have a single opening, but more typically they have two or more openings. A cooling medium (eg, air, water or oil) is circulated through the cooling channel(s) to remove the heat generated during grinding.

In some embodiments, the polymeric binder abrasive article 198 may be further infused with an infiltrant to densify and strengthen the part. In one non-limiting example, the polymeric binder abrasive particles 198 may be immersed in a polymeric penetrant, and the polymeric material may be allowed to enter any unwanted voids within the part. The polymeric penetrant can then be cured or hardened to strengthen the impregnated part or otherwise change its properties for a particular application.

The polymer binder abrasive article 198 may be optionally machined or attached to a metal mandrel, such as a single structured abrasive disk, abrasive bit, abrasive segment, shaped abrasive particle (eg, triangular abrasive particle); Suitable grinding parts such as abrasive wheels and the like can be formed.

Referring now to FIG. 2 , an exemplary polymer bond abrasive wheel 200 has arcuate and meander cooling channels 210 , respectively.

3 shows another exemplary polymer binder abrasive wheel 300 with meandering cooling channels 320 .

4 shows an exemplary polymer binder abrasive segment 400 . In typical use, a plurality of polymer binder abrasive segments 400 are mounted uniformly spaced along the circumference of a metal disk to form an abrasive wheel.

5 shows a polymer binder abrasive disk 500 having two regions 510 and 520 . Each region has abrasive particles 530 and 540 retained within a polymeric binder matrix material 550 and 560, respectively.

6A and 6B and FIGS. 7A and 7B show various unitary structured abrasive disks in which precision-shaped abrasive elements 610 and 710 are integrally formed with planar bases 620 and 720, respectively.

8 shows a rotary abrasive tool 800 (eg, a bit for a handheld motor drive shaft such as a Dremel tool).

The aforementioned polymeric abrasive wheels shown in FIGS. 2 and 3 heat a corresponding raw abrasive article precursor body (ie, include polymeric binder precursor particles having the same general shape characteristics but held together by a temporary binder) or Alternatively, it can be prepared by conversion.

selected embodiments of the present invention

Embodiment A: A polymeric binder abrasive article comprising a polymeric binder material having abrasive particles retained within a polymeric matrix, the polymeric binder abrasive article comprising meandering cooling channels and arcuate cooling channels extending at least partially through the abrasive article A polymer binder abrasive article having at least one of:

Embodiment B. The polymer bond of Embodiment A, wherein the abrasive particles comprise first abrasive particles and second abrasive particles, wherein the first abrasive particles and the second abrasive particles are disposed in different predetermined regions within the polymer binder abrasive article. Article abrasive.

Embodiment C. The polymeric binder abrasive article of embodiment A or embodiment B, wherein the different regions are layers.

Embodiment D. The polymer binder abrasive article of any one of Embodiments A-C, wherein the abrasive particles comprise at least one of diamond particles or cubic boron nitride particles.

Embodiment E. The polymeric binder abrasive article of any one of Embodiments A through D, wherein the abrasive particles comprise at least one of silicon carbide, boron carbide, silicon nitride, or metal oxide ceramic particles.

Embodiment F. The polymer bond abrasive article of any one of embodiments A-E, wherein the polymer bond abrasive article is selected from a single structured abrasive disk, abrasive grinding bit, abrasive segment, and abrasive wheel.

Embodiment G. A polymeric binder abrasive article precursor comprising abrasive particles bonded to a polymer matrix, the polymeric binder abrasive article precursor comprising: at least one meandering cooling channel extending at least partially through the polymeric binder abrasive article precursor; or at least one arcuate cooling channel extending at least partially through the polymer binder abrasive article precursor.

Embodiment H. The polymer binder abrasive article precursor of embodiment G, wherein the abrasive particles comprise at least one of silicon carbide, boron carbide, silicon nitride, or metal oxide ceramic particles.

Embodiment I. A method of making an abrasive article comprising:

a)

i) depositing a layer of sparse powder particles in the defined area, the sparse powder particles comprising polymeric binder precursor particles and abrasive particles, the layer of sparse powder particles having a substantially uniform thickness;

ii) applying a liquid binder precursor material to a predetermined area of the layer of sparse powder particles;

iii) converting the liquid binder precursor material to a temporary binder material, wherein the temporary binder material is bonded to at least a portion of the abrasive particles and the polymeric binder precursor particles in the predetermined region to form a layer of bonded powder particles;

A sub-process comprising;

b) independently, performing step a) multiple times to produce an abrasive article preform comprising bonded powder particles and remaining coarse powder particles, wherein in each step a) the coarse powder particles are independently selected and the liquid binder precursor material is independently selected; and

c) converting the polymeric binder precursor particles in the abrasive article preform to polymeric binder particles, the polymeric binder particles retaining the abrasive particles to form the polymeric binder abrasive article;

A method of manufacturing an abrasive article comprising:

Embodiment J. The method of making the abrasive article of embodiment I, wherein the abrasive particles comprise at least one of diamond particles, cubic boron nitride particles, or metal oxide ceramic particles.

Embodiment K. The method of making the abrasive article of embodiment I or J, wherein the liquid binder precursor material comprises a liquid carrier having a polymer dissolved or dispersed therein.

Embodiment L. The abrasive article of any one of Embodiments I-K, further comprising separating substantially all remaining coarse powder particles from the abrasive article preform prior to the conversion step (c). manufacturing method.

Embodiment M. The method of making the abrasive article of any one of Embodiments I-L, wherein the coarse powder particles comprise submicron ceramic particles.

Embodiment N. The method of making the abrasive article of any one of Embodiments I through M, wherein the polymeric binder precursor particles are selected from a urethane resin, an epoxy resin, a phenolic resin, and combinations thereof.

Embodiment O. Embodiments I through, wherein the converting step (c) comprises heating the abrasive article preform to a temperature sufficient to at least partially soften the polymeric binder precursor particles to form polymeric binder particles. The method of making the abrasive article of any one of Form N.

Embodiment P. The method of Embodiment I through O, wherein the converting step (c) comprises heating the abrasive article preform to a temperature sufficient to polymerize the polymeric binder precursor particles to form polymeric binder particles. The method of making the abrasive article of any one of the embodiments.

Embodiment Q. The converting step (c) comprises heating a selected portion of the abrasive article preform to a temperature sufficient to at least partially soften or polymerize the polymeric binder precursor particles to form polymeric binder particles. , the method of making the abrasive article of any one of Embodiments I-P.

Embodiment R. The method of making the abrasive article of any one of Embodiments I-Q, wherein the abrasive article preform is heated to a temperature of from about 150°C to about 250°C.

Embodiment S. Embodiments I through (c) comprising applying a polymerizing agent to the abrasive article preform to at least partially polymerize the polymeric binder precursor particles to form polymeric binder particles The method of making the abrasive article of any one of R.

Embodiment T. The method of making the abrasive article of any one of Embodiments I-S, further comprising heating the coarse powder particles prior to step (a)(ii).

Embodiment U. The method of making the abrasive article of any one of Embodiments I through T, wherein the coarse powder particles are heated to a temperature of about 30° C. or less.

Embodiment V. The method of making the abrasive article of any one of Embodiments I-U, wherein the temporary binder material comprises polyvinyl pyrrolidone.

Embodiment W. A method of making an abrasive article comprising:

a)

i) depositing a layer of sparse powder particles in the defined area, wherein the sparse powder particles comprise from about 5% to about 95% by weight of the polymeric binder precursor particles and from about 5% to about 95% by weight of the abrasive particles; , wherein the layer of coarse powder particles has a substantially uniform thickness;

ii) spraying a liquid binder precursor material onto predetermined areas of the layer of sparse powder particles; and

iii) converting the liquid binder precursor material into a temporary binder material that bonds the particles of sparse powder particles together in a predetermined area to form a layer of bonded powder particles;

A sub-process comprising;

b) independently, performing step a) multiple times to produce an abrasive article preform comprising bonded powder particles and remaining coarse powder particles, wherein in each step a) the coarse powder particles are independently selected and the liquid binder precursor material is independently selected; and

(c) curing the polymeric binder precursor particles by heating the polymeric binder precursor particles in the abrasive article preform to form polymeric binder particles, wherein the polymeric binder particles retain the abrasive particles to form the polymeric binder abrasive article. step to form

A method of manufacturing an abrasive article comprising:

Embodiment X. The method of making the abrasive article of embodiment W, further comprising heating the coarse powder particles to a temperature of about 30° C. or less prior to step (a)(ii).

Embodiment Y. The method of making the abrasive article of embodiment W or embodiment X, further comprising separating substantially all remaining coarse powder particles from the abrasive article preform prior to the conversion step (c).

Embodiment Z. The method of making the abrasive article of any one of embodiments W through Y, wherein the sparse powder particles further comprise polymeric binder precursor particles.

Embodiment AA. Any of embodiments W through Z further comprising sintering the polymer bonded abrasive article after step (c) to convert the polymer binder precursor particles to polymer binder particles and form the polymer bonded abrasive article A method of making an abrasive article of one embodiment.

Embodiment BB. The method of making the abrasive article of any one of embodiments W-AA, further comprising impregnating the polymer-bonded abrasive article with a polymer penetrant.

Although the objects and advantages of the present invention are further illustrated by the following non-limiting examples, the specific materials and amounts thereof recited in these examples, as well as other conditions and details, should not be construed as unduly limiting the present invention. is not

Example

General process description:

A mixture of polymer powder and abrasive particles was prepared and placed in the feed chamber of an X-One M-LAB 3D printer obtained from The X-One Company, North Huntingdon, PA. The printer's binder supply bottle was filled with an etheric solvent-based polymer binder obtained from X1 as PM-B-SR1-04.

The 3D model was prepared as a file to produce exemplary parts for the rotary tool and polishing geometry, and this file was prepared as a print job for the X1 M-lab printer.

After printing, the printed segments and parts were extracted and depulverized and found to be fairly stable. These segments and parts were placed on a metal mandrel and placed in an oven to densify the powder around the agglomerates and attach the 3D shape to the metal mandrel. The densified parts were evaluated for polishing performance as described below.

Example 1

The powder mixture was prepared by mixing 67 wt % polyurethane powder and 33 wt % 9 from Lubrizol X2006-NAT-025PWD (Lubrizol Advanced Materials, Brexville, Ohio). μm diamond agglomerates (3M Company, Cumberland, Wis. 012116-SD1). The 3D model used to create the part was a hollow cylinder with a cap. The shaped parts were printed on an X-One M-lab 3D printer. The bed height was 100 μm, the spreader speed was 5 mm/min, the print saturation was set at the nominal 90% level, and the drying time was set to 15 seconds with the heater output set to 50%. The binder was X1 PM-B-SR1-04.

The part was de-pulverized (FIG. 9) and placed on a 3 mm diameter steel mandrel as shown in the photograph of FIG. The part was then cured at 210° C. for 1 hour. A photograph of the resulting cured article is shown in FIG. 11 .

Example 2

A powder mixture was prepared as in Example 1: 67% polyurethane powder and 33% 9 μm diamond agglomerates from Lubrizol X2006-NAT-025PWD (3M, Cumberland, Wis. 012116-SD1). The 3D model used to create the part was a truncated cone on a hollow cylinder. The shaped parts were printed on an X-One M-lab 3D printer. The bed height was 100 μm, the spreader speed was 5 mm/min, the print saturation was set at the nominal 90% level, and the drying time was set to 15 seconds with the heater output set to 50%. The binder was X1 PM-B-SR1-04.

The part was de-pulverized (FIG. 9) and placed on a small amount of diamond agglomerate (unique) in an aluminum tray. The part was then cured at 210° C. for 1 hour. A photograph of the resulting cured article is shown in FIG. 11 .

Example 3

A powder mixture was prepared as in Example 1: 67% polyurethane powder and 33% 9 μm diamond agglomerates from Lubrizol X2006-NAT-025PWD (3M, Cumberland, Wis. 012116-SD1). The 3D model used to create the part was a cylinder with an arcuate groove around the outer perimeter and a rounded top, with the top having a radially aligned inverted tapered conical hole that connects to a blind central hole along the axis of the cylinder. . The shaped parts were printed on an X-One M-lab 3D printer. The bed height was 100 μm, the spreader speed was 5 mm/min, the print saturation was set at the nominal 90% level, and the drying time was set to 15 seconds with the heater output set to 50%. The binder was X1 PM-B-SR1-04.

The part was de-pulverized, and a photograph of the de-pulverized part is shown in FIG. 12 .

Example 4

The powder mixture was mixed with 30 wt % 3M Scotchkote 6258 epoxy (3M Company, St. Paul, Minn.) and 70 wt % P280 alumina abrasive (Imerys Fused Minerals, Villach, Austria). GmbH)). The 3D model used to create the part was a hollow cylinder with a cap. The shaped parts were printed on an X-One M-lab 3D printer. The bed height was 100 μm, the spreader speed was 5 mm/min, the print saturation was set to the nominal 90% level, and the drying time was set to 15 seconds with the heater output set to 80%. The binder was X1 PM-B-SR1-04.

The part was de-pulverized, and a photograph of the de-pulverized part is shown in FIG. 13 . The cylinder part was placed on a steel shaft and cured (hardened) at 125° C. for 45 minutes. A photograph of the printed part after curing is shown in FIG. 14 .

Polishing result

The mandrel tool of Example 1 as shown in FIG. 11 was provided for wet polishing of zirconia. A zirconia coupon having a surface of 15 mm x 20 mm dimensions was polished for approximately 30 seconds by applying a 100-250 gram force (gf) onto a mandrel rotating at 15,000 rpm.

Each force condition was run on a separate zirconia coupon. During the duration of the applied force, the tool was moved in a constant manner to affect an area of dimensions of about 5 mm x 5 mm.

After polishing, the gloss of the sample was measured and is shown in FIG. 15 . The 60 degree gloss GU (gloss units) was measured after polishing using a Novo-Curve gloss meter from Rhopoint Instruments (East Sussex, UK). Zirconia samples were measured for gloss in two perpendicular directions (“Gloss 1” and “Gloss 2”). The material loss for 200 and 250 gf was about 1 mg per minute, and for other conditions the loss was below the measurable limit. During and after polishing, the 3D polymer binder abrasive geometry showed no cracks and no signs of separation from the mandrel.

All cited references, patents, and patent applications in the above application for patent applications are hereby incorporated by reference in their entirety and in a consistent manner. In case of inconsistency or inconsistency between portions of this application and incorporated references, the information in the foregoing description shall control. The foregoing description, given to enable any person skilled in the art to practice the claimed invention, should not be construed as limiting the scope of the invention, which is defined by the claims and all equivalents thereto.

Claims (20)

delete delete delete delete a) i) depositing a layer of loose powder particles in a defined area, said loose powder particles comprising polymeric binder precursor particles and abrasive particles, said layer of loose powder particles having a uniform thickness , step;
ii) applying a liquid binder precursor material to a predetermined area of the layer of sparse powder particles; and
iii) converting the liquid binder precursor material to a temporary binder material, wherein the temporary binder material is bonded to at least a portion of the abrasive particles and the polymeric binder precursor particles in the predetermined region to form a layer of bonded powder particles. forming steps
A sub-process step comprising;
b) independently, performing step a) multiple times to produce an abrasive article preform comprising said bonded powder particles and remaining coarse powder particles, wherein in each step a) said coarse powder particles wherein the powder particles are independently selected and the liquid binder precursor material is independently selected; and
c) converting the polymeric binder precursor particles in the abrasive article preform to polymeric binder particles, wherein the polymeric binder particles retain abrasive particles to form a polymeric binder abrasive article;
A method of manufacturing an abrasive article comprising: 6. The method of claim 5,
Before the conversion step (c),
separating all remaining coarse powder particles from the abrasive article preform;
A method of manufacturing an abrasive article further comprising a. 7. The method according to claim 5 or 6,
The conversion step (c) is,
heating the abrasive article preform to a temperature sufficient to at least partially soften the polymeric binder precursor particles to form the polymeric binder particles, or
heating the abrasive article preform to a temperature sufficient to polymerize the polymeric binder precursor particles to form the polymeric binder particles, or
heating selected portions of the abrasive article preform to a temperature sufficient to at least partially soften the polymeric binder precursor particles to form the polymeric binder particles;
including,
Optionally, the abrasive article preform is heated to a temperature between 150°C and 250°C. 7. The method according to claim 5 or 6,
wherein said converting step (c) comprises applying a polymerizing agent to said abrasive article preform to at least partially polymerize said polymeric binder precursor particles to form polymeric binder particles. 7. The method according to claim 5 or 6,
and heating the coarse powder particles prior to step (a)(ii). delete delete delete delete delete delete delete delete delete delete delete

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